<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        .box1{
            width: 200px;
            height: 200px;
            background-color: pink;
            position: absolute;
            top: 0px;
            left: 0px;
            z-index: 1
        }

        .box2{
            width: 200px;
            height: 200px;
            background-color: blueviolet;
            position: absolute;
            top: 20px;
            left: 20px;
            z-index: 2;
        }

        .box3{
            width: 200px;
            height: 200px;
            background-color: aquamarine;
            position: absolute;
            top: 50px;
            left: 50px;
            z-index: 999;
        }
    </style>
</head>
<body>
    <div class="box1"></div>
    <div class="box2"></div>
    <div class="box3"></div>
</body>
</html>